Derivation of an Effective Thermal Electrochemical Model for Porous Electrode Batteries using Asymptotic Homogenisation

TL;DR

This paper develops a systematic, homogenised thermal electrochemical model for porous batteries that captures microstructural effects and thermal dynamics, improving upon ad hoc models and enabling more accurate simulations.

Contribution

It introduces a new asymptotic homogenisation approach to derive effective macroscale models from microscale equations for porous batteries.

Findings

The homogenised model includes thermal effects and microstructure anisotropy.

Comparison shows the model aligns well with the Doyle-Fuller-Newman model.

Systematic derivation enhances model accuracy and computational efficiency.

Abstract

Thermal electrochemical models for porous electrode batteries (such as lithium ion batteries) are widely used. Due to the multiple scales involved, solving the model accounting for the porous microstructure is computationally expensive, therefore effective models at the macroscale are preferable. However, these effective models are usually postulated ad hoc rather than systematically upscaled from the microscale equations. We present an effective thermal electrochemical model obtained using asymptotic homogenisation, which includes the electrochemical model at the cell level coupled with a thermal model that can be defined either at the cell or the battery level. The main aspects of the model are the consideration of thermal effects, the diffusion effects in the electrode particles, and the anisotropy of the material based on the microstructure, all of them incorporated in a systematic manner. We also compare the homogenised model with the standard electrochemical Doyle, Fuller & Newman model.